Pathophysiological mechanisms of major depressive disorder (MDD) seem to be associated with oxidative stress pathways and altered purinergic metabolism. We conducted a systematic review and meta-analysis to estimate if subjects with MDD might have reduced levels of antioxidant uric acid, considering also potential influence of antidepressant treatment. We searched the main Electronic Databases, identifying 14 studies that met our inclusion criteria. Meta-analyses were carried out generating pooled Hedges' g and mean differences (MDs), using random-effects models. Heterogeneity across studies and risk of publication bias were estimated using standard methods. Relevant sensitivity and meta-regression analyses were conducted. Subjects with MDD had levels of uric acid lower than healthy controls (Hedges' g = -0.30; p = 0.003). Overall between-study heterogeneity was high (I = 76.3%). The effect was significant among studies including drug naïve/free MDD individuals (Hedges' g = -0.55; p = 0.023), but not among those involving treated subjects (Hedges' g = -0.15; p = 0.062). Relevant quality- and heterogeneity-based sensitivity analyses, as well as meta-regressions, confirmed these findings. In addition, uric acid levels significantly, though inconsistently (I = 79.2%), increased after treatment (MD = +0.71 mg/dL; p < 0.001), regardless of follow-up duration (p = 0.518). Our meta-analysis shows that subjects with MDD have lower levels of uric acid. Since antidepressant treatment seems to influence this association, our findings support the hypothesis that uric acid levels may represent a state marker of MDD. Nevertheless, the potential role of additional factors that might clarify the nature of this association deserves further research.
Background: Subjects with mental disorders have a higher risk of suicide behaviors than the general population. So, to date, researchers have investigated some biomarkers possibly related to suicidality. Despite many studies have reported a possible relationship between low lipid serum levels and suicide attempt, conflicting results have emerged. Aim We investigated whether serum total cholesterol, LDL cholesterol and triglycerides are associated with recent suicide attempts in subjects with different mental disorders. Methods We conducted a cross-sectional study, including 593 consecutively admitted inpatients with schizophrenia spectrum, bipolar, major depressive, and personality disorders. Serum lipid levels were compared between subjects admitted for a recent suicide attempt and those without such recent history. Moreover, according to hypothesis that links impulsivity and violence with low serum lipid levels, the association between lipid levels and violent suicide attempt was assessed. Results We did not find any association of total and LDL cholesterol and triglycerides with suicide attempts, also considering diagnosis and suicide methods. In addition, a post-hoc analysis showed a trend toward significance (p=0.06) in the association between high cholesterol level (≥160mg/dL) and recent suicide attempt. Conclusions Our results do not support the hypothesis of association between lipid profiles and suicide attempts in subjects with different mental disorders. Further research is needed to clarify the role of biomarkers in suicidal behaviors.
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